"perceptional experiences. While it is possible to imagine what it would be like to fly, navigate by sonar, hang upside down and eat insects like a bat, that is not the same as a bat's perspective. Nagel claims that even if humans were able to metamorphose gradually into bats, their brains would not have been wired as a bat's from birth; therefore, they would only be able to experience the life and behaviors of a bat, rather than the mindset. Such is the difference between subjective and objective points of view. According to Nagel, ""our own mental activity is the"
"gliding: Bats are the only mammal with flapping or powered flight. A few other mammals glide or parachute; the best known are flying squirrels and flying lemurs. Flying and gliding animals A number of animals have evolved aerial locomotion, either by powered flight or by gliding. Flying and gliding animals (""volant"" animals) have evolved separately many times, without any single ancestor. Flight has evolved at least four times, in the insects, pterosaurs, birds, and bats. Gliding has evolved on many more occasions. Usually the development is to aid canopy animals in getting from tree to tree, although there are other"
"other groups of arthropods. Bats are the only mammals capable of sustaining level flight (see ""bat flight""). However, there are several gliding mammals which are able to glide from tree to tree using fleshy membranes between their limbs; some can travel hundreds of meters in this way with very little loss in height. Flying frogs use greatly enlarged webbed feet for a similar purpose, and there are flying lizards which fold out their mobile ribs into a pair of flat gliding surfaces. ""Flying"" snakes also use mobile ribs to flatten their body into an aerodynamic shape, with a back and"
"However most other birds and all powered aircraft need a source of propulsion to climb. This is termed powered flight. The only groups of living things that use powered flight are birds, insects, and bats, while many groups have evolved gliding. The extinct Pterosaurs, an order of reptiles contemporaneous with the dinosaurs, were also very successful flying animals. Each of these groups' wings evolved independently. The wings of the flying vertebrate groups are all based on the forelimbs, but differ significantly in structure; those of insects are hypothesized to be highly modified versions of structures that form gills in most"
"is exclusively bipedal is the birds, which have either an alternating or a hopping gait. There are also a number of bipedal mammals. Most of these move by hopping – including the macropods such as kangaroos and various jumping rodents. Only a few mammals such as humans and the ground pangolin commonly show an alternating bipedal gait. Cockroaches and some lizards may also run on their two hind legs. With the exception of the birds, terrestrial vertebrate groups with legs are mostly quadrupedal – the mammals, reptiles, and the amphibians usually move on four legs. There are many quadrupedal gaits."
"Flightless cormorant The flightless cormorant (""Phalacrocorax harrisi""), also known as the Galapagos cormorant, is a cormorant native to the Galapagos Islands, and an example of the highly unusual fauna there. It is unique in that it is the only cormorant that has lost the ability to fly. Once it was placed in its own genus, ""Nannopterum"" or ""Compsohalieus"", although current taxonomy places it in the genus with most of the other cormorants, ""Phalacrocorax"". Like all cormorants, this bird has webbed feet and powerful legs that propel it through ocean waters as it seeks its prey of fish, eels, small octopuses,"
"Bird Birds, also known as Aves, are a group of endothermic vertebrates, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. Birds live worldwide and range in size from the bee hummingbird to the ostrich. They rank as the world's most numerically-successful class of tetrapods, with approximately ten thousand living species, more than half of these being passerines, sometimes known as perching birds. Birds have which are more or less developed depending on the species; the only known groups without wings are the extinct moa"
"[[File:Israeli Bats - 26 September 2015.webm|thumb|upright=1.35|Slow-motion and normal speed of [[Egyptian fruit bat]]s flying]] Bats are the only mammals that can truly fly. They fly through the air at a constant speed by moving their wings up and down (usually with some fore-aft movement as well). Because the animal is in motion, there is some airflow relative to its body which, combined with the velocity of the wings, generates a faster airflow moving over the wing. This generates a lift force vector pointing forwards and upwards, and a drag force vector pointing rearwards and upwards. The upwards components of these"
"also included here. Flightless bird Flightless birds are birds that through evolution lost the ability to fly. There are over 60 extant species including the well known ratites (ostrich, emu, cassowary, rhea and kiwi) and penguins. The smallest flightless bird is the Inaccessible Island rail (length 12.5 cm, weight 34.7 g). The largest (both heaviest and tallest) flightless bird, which is also the largest living bird, is the ostrich (2.7 m, 156 kg). Ostriches are farmed for their decorative feathers, meat and their skins, which are used to make leather. Many domesticated birds, such as the domestic chicken and domestic"
"Flightless bird Flightless birds are birds that through evolution lost the ability to fly. There are over 60 extant species including the well known ratites (ostrich, emu, cassowary, rhea and kiwi) and penguins. The smallest flightless bird is the Inaccessible Island rail (length 12.5 cm, weight 34.7 g). The largest (both heaviest and tallest) flightless bird, which is also the largest living bird, is the ostrich (2.7 m, 156 kg). Ostriches are farmed for their decorative feathers, meat and their skins, which are used to make leather. Many domesticated birds, such as the domestic chicken and domestic duck, have lost"
"within the species range, and the prevention of fishing with nets in the bird's foraging range. Flightless cormorant The flightless cormorant (""Phalacrocorax harrisi""), also known as the Galapagos cormorant, is a cormorant native to the Galapagos Islands, and an example of the highly unusual fauna there. It is unique in that it is the only cormorant that has lost the ability to fly. Once it was placed in its own genus, ""Nannopterum"" or ""Compsohalieus"", although current taxonomy places it in the genus with most of the other cormorants, ""Phalacrocorax"". Like all cormorants, this bird has webbed feet and powerful legs"
"on one side with the middle on the other side. Insects are the only invertebrates to have evolved flight, and all flying insects derive from one common ancestor. Many insects spend at least part of their lives under water, with larval adaptations that include gills, and some adult insects are aquatic and have adaptations for swimming. Some species, such as water striders, are capable of walking on the surface of water. Insects are mostly solitary, but some, such as certain bees, ants and termites, are social and live in large, well-organized colonies. Some insects, such as earwigs, show maternal care,"
"are capable of doing so. These modes of locomotion typically require an animal start from a raised location, converting that potential energy into kinetic energy and using aerodynamic forces to control trajectory and angle of descent. Energy is continually lost to drag without being replaced, thus these methods of locomotion have limited range and duration. Powered flight has evolved only four times (first in insects, then in pterosaurs, birds and bats). It uses muscular power to generate aerodynamic forces and to replace energy lost to drag. Ballooning and soaring are not powered by muscle, but rather by external aerodynamic sources"
"Invertebrate Invertebrates are animals that neither possess nor develop a vertebral column (commonly known as a ""backbone"" or ""spine""), derived from the notochord. This includes all animals apart from the subphylum Vertebrata. Familiar examples of invertebrates include insects; crabs, lobsters and their kin; snails, clams, octopuses and their kin; starfish, sea-urchins and their kin; jellyfish, and worms. The majority of animal species are invertebrates; one estimate puts the figure at 97%. Many invertebrate taxa have a greater number and variety of species than the entire subphylum of Vertebrata. Some of the so-called invertebrates, such as the Tunicata and Cephalochordata are"
"The non-flying penguins have wings adapted for use under water and use the same wing movements for swimming that most other birds use for flight. Most small flightless birds are native to small islands, and lead a lifestyle where flight would offer little advantage. Among living animals that fly, the wandering albatross has the greatest wingspan, up to ; the great bustard has the greatest weight, topping at . Most species of insects can fly as adults. Insect flight makes use of either of two basic aerodynamic models: creating a leading edge vortex, found in most insects, and using clap"
"Kakapo The kakapo (Māori: kākāpō) or ""night parrot"", also called owl parrot (""Strigops habroptilus""), is a species of large, flightless, nocturnal, ground-dwelling parrot of the super-family Strigopoidea, endemic to New Zealand. It has finely blotched yellow-green plumage, a distinct facial disc, a large grey beak, short legs, large feet, and relatively short wings and tail. A combination of traits make it unique among its kind; it is the world's only flightless parrot, the heaviest parrot, nocturnal, herbivorous, visibly sexually dimorphic in body size, has a low basal metabolic rate and no male parental care, and is the only parrot to"
"Insect flight Insects are the only group of invertebrates that have evolved wings and flight. Two insect groups, the dragonflies and the mayflies, have flight muscles attached directly to the wings. Other insects have the flight muscles attached to the thorax, making it oscillate and indirectly causing the wings to beat. Some very small insects make use not of steady-state aerodynamics but of the Weis-Fogh clap and fling mechanism, generating large lift forces at the expense of wear and tear on the wings. Many insects can hover, maintaining height and controlling their position. Some insects such as moths have the"
"Bat flight Bats are the only mammal capable of true flight. Bats use flight for capturing prey, breeding, avoiding predators, and long-distance migration. Bat wing morphology is often highly specialized to the needs of the species. Charles Darwin foresaw an issue with his theory of evolution by natural selection in the evolution of complex traits such as eyes or ""the structure and habits of a bat."" Indeed, the oldest bat fossils are very similar in wing morphology to the bats of today, despite living and dying 52.5 million years ago. The common ancestor of all bats is hypothesized to have"
"can hover for a short period of time. Although not a true hover, some birds remain in a fixed position relative to the ground or water by flying into a headwind. Kestrels, terns and even hawks use this wind hovering. Most birds that hover have high aspect ratio wings that are suited to low speed flying. One major exception to this are the hummingbirds, which are the most accomplished hoverers of all the birds. Hummingbird flight is different from other bird flight in that the wing is extended throughout the whole stroke, the stroke being a symmetrical figure of eight,"
"in fairly small groups within caves, animal burrows, or hollow trees, although some species aggregate in colonies of several hundred individuals. They do not hibernate, although some species have been reported to aestivate. The second most diverse group of mammals behind rodents, bats—order Chiroptera—are uniquely the only group of mammal that has evolved the ability to fly. First appearing in the Eocene epoch, they are believed to have evolved from an arboreal gliding ancestor possibly originating in South America. It is thought that the membrane that makes up the bat wing, along with the uropatagium—the membrane stretching between the legs"
"weight of their bodies. The primate version of bipedalism is unusual because the back is close to upright (completely upright in humans). Many primates can stand upright on their hind legs without any support. Chimpanzees, bonobos, gibbons and baboons exhibit forms of bipedalism. On the ground sifakas move like all indrids with bipedal sideways hopping movements of the hind legs, holding their forelimbs up for balance. Geladas, although usually quadrupedal, will sometimes move between adjacent feeding patches with a squatting, shuffling bipedal form of locomotion. Humans are the only primates who are normally biped, due to an extra curve in"
"The most diverse group of animals on earth, the insects, are included in a larger taxon known as hexapods, most of which are hexapedal, walking and standing on six legs. Exceptions among the insects include praying mantises and water scorpions, which are quadrupeds with their front two legs modified for grasping, some butterflies such as the Lycaenidae (blues and hairstreaks) which use only four legs, and some kinds of insect larvae that may have no legs (e.g., maggots), or additional prolegs (e.g., caterpillars). Spiders and many of their relatives move on eight legs – they are octopedal. However, some creatures"
"lizards) in Asian forests may be a factor. In Australia, many mammals (and all mammalian gliders) possess, to some extent, prehensile tails. Powered flight has evolved unambiguously only four times—birds, bats, pterosaurs, and insects. In contrast to gliding, which has evolved more frequently but typically gives rise to only a handful of species, all three extant groups of powered flyers have a huge number of species, suggesting that flight is a very successful strategy once evolved. Bats, after rodents, have the most species of any mammalian order, about 20% of all mammalian species. Birds have the most species of any"
"Flying and gliding animals A number of animals have evolved aerial locomotion, either by powered flight or by gliding. Flying and gliding animals (""volant"" animals) have evolved separately many times, without any single ancestor. Flight has evolved at least four times, in the insects, pterosaurs, birds, and bats. Gliding has evolved on many more occasions. Usually the development is to aid canopy animals in getting from tree to tree, although there are other possibilities. Gliding, in particular, has evolved among rainforest animals, especially in the rainforests in Asia (most especially Borneo) where the trees are tall and widely spaced. Several"
"is considered the limit for avian flight. The ""heaviest"" extant flying birds are known to weigh up to (there are several contenders, among which are the European great bustard and the African kori bustard). A mute swan, which may have personally lost the power of flight due to extreme weight, was found to have weighed . Meanwhile, the sarus crane is the tallest flying bird alive, at up to tall, standing about as high as ""Argentavis"" due to its long legs and neck. The largest known flying creatures overall are not birds, but instead the azhdarchid pterosaurs of the Cretaceous."
"periods of soaring in rising air, and so spend a considerable time airborne with a minimal expenditure of energy. The great frigatebird in particular is capable of continuous flights up to several weeks. To assist gliding, some mammals have evolved a structure called the patagium. This is a membranous structure found stretched between a range of body parts. It is most highly developed in bats. For similar reasons to birds, bats can glide efficiently. In bats, the skin forming the surface of the wing is an extension of the skin of the abdomen that runs to the tip of each"
"be very long-lived. The chowchilla, the sole species with any banding data, has an average lifespan of around five years and has been known to live for seventeen. Orthonychidae The logrunners (Orthonyx) are a clade of birds which comprises three species of passerine birds endemic to Australia and New Guinea. Some authorities consider the Australian family Cinclosomatidae to be part of the Orthonychidae. The three species use their stiffened tails to brace themselves when feeding. The species are: The Australian logrunner, ""Orthonyx temminckii"", is from northeastern New South Wales and southeast Queensland, where it is very local in its distribution,"
"location. Sailplanes, hang gliders and paragliders have complete directional control and fly freely. Creatures able to launch themselves into the air and glide short distances include: Unpowered flights of longer duration and distance are possible if rising air is used to gain energy. This can further reduce the rate of descent or even increase height, which is known as ""soaring"". Soaring is where the object/animal obtains additional energy from rising air without exerting any power to remain airborne. An example is the albatross, which is a large seabird renowned for its ability to stay aloft by soaring above the waves"
"for weeks continuously, this seems to be the obvious result. However, sleep in flight has not been recorded, and is so far unsupported by EEG data. Further research may explain whether birds sleep during flight or if there are other mechanisms which ensure their remaining healthy during long flights in the absence of sleep. Unlike in birds, very few consistent features of sleep have been found among reptile species. The only common observation is that reptiles do not have REM sleep. Sleep in some invertebrates has also been extensively studied, e.g., sleep in fruitflies (Drosophila) and honeybees. Some of the"
"around 20 kilograms. Other structural adaptations of flying animals include reduced and redistributed body weight, fusiform shape and powerful flight muscles; there may also be physiological adaptations. Active flight has independently evolved at least four times, in the insects, pterosaurs, birds, and bats. Insects were the first taxon to evolve flight, approximately 400 million years ago (mya), followed by pterosaurs approximately 220 mya, birds approximately 160 mya, then bats about 60 mya. Rather than active flight, some (semi-) arboreal animals reduce their rate of falling by gliding. Gliding is heavier-than-air flight without the use of thrust; the term ""volplaning"" also"
"will at least guard their eggs, and sometimes continue guarding their offspring until adulthood, and possibly even feeding them. Another simple form of parental care is to construct a nest (a burrow or an actual construction, either of which may be simple or complex), store provisions in it, and lay an egg upon those provisions. The adult does not contact the growing offspring, but it nonetheless does provide food. This sort of care is typical for most species of bees and various types of wasps. Insects are the only group of invertebrates to have developed flight. The evolution of insect"
"another is that they functioned in parachuting, then gliding, then flight for originally arboreal insects. Pterosaurs were the next to evolve flight, approximately 228 million years ago. These reptiles were close relatives of the dinosaurs (and sometimes mistakenly considered dinosaurs by laymen), and reached enormous sizes, with some of the last forms being the largest flying animals ever to inhabit the Earth, having wingspans of over 9.1 m (30 ft). However, they spanned a large range of sizes, down to a 250 mm (10 in) wingspan in ""Nemicolopterus"". Birds have an extensive fossil record, along with many forms documenting both"
"of animals. Normal humans may be considered ""obligate"" bipeds because the alternatives are very uncomfortable and usually only resorted to when walking is impossible. There are a number of states of movement commonly associated with bipedalism. The great majority of living terrestrial vertebrates are quadrupeds, with bipedalism exhibited by only a handful of living groups. Humans, gibbons and large birds walk by raising one foot at a time. On the other hand, most macropods, smaller birds, lemurs and bipedal rodents move by hopping on both legs simultaneously. Tree kangaroos are able to walk or hop, most commonly alternating feet when"